1. Field of the Invention
The present invention relates broadly to military bridging. Military bridges are employed for crossing wet and dry gaps in three general situations: under enemy fire, for temporary mobility, and for long-term logistical support. The present invention is directed specifically to providing temporary bridging in support of tactical operations, while not under enemy fire, by utilizing a bridge module which includes foldable units carried by a bridge truck or transporter.
2. Description of the Related Art
Previously, the practice with bridge spans of this type has been to utilize structures wherein small slender elements are rigidly spaced into closed cellular geometries which are strong and stiff in both bending and torsion. The resulting roadways have box beams and space frames, both of which enclose large volumes of air and, thus, are bulky.
Prior military bridges are not known to have employed fibrous composite materials (graphite, Kevlar, glass, etc.) since these materials were considered to be too costly for such a structure. Also, it has always been assumed that labor is cheap and available for military purposes, such as the erection and placement of the bridges. In this regard, this is not the case where a mobile force is putting a bridge in place.
In the past, bridges made up of multiple duplicate components have been utilized. However, structural or mechanical repair in the field is not practical for a mobile force in view of the limited resources of such a force. The only field repair practical is replacement. Thus, bridges made up of modules which have few parts and can be scavanged and replaced are now necessary.